*{
    margin: 0;
    padding: 0;
    /* font-family: ''; */
}
body{
    display: flex;
    /* 主轴对齐方式 */
    justify-content: center;
    /* 副轴对齐方式 */
    align-items: center;
    min-height: 100vh;
    flex-direction: column;
    background: rgb(201, 234, 247);
}
a{
    position: relative;
    display: inline-block;
    padding: 12px 36px;
    margin: 10px 0;
    color: #ffffff;
    /* 去下划线 */
    text-decoration: none;
    /* 大写 */
    text-transform: uppercase;
    font-size: 18px;
    letter-spacing: 2px;
    border-radius: 40px;
    
    /* 当元素溢出时会发生的;hidden内容会被裁剪 */
    overflow: hidden;

    /* 背景渐变色 */
    background: linear-gradient(90deg,#0162c8,#55e7fc);
}

a:nth-child(2){
    background: linear-gradient(90deg,#b603b6,#ec41b3,#ffb9f0);
}
a:nth-child(3){
    background: linear-gradient(90deg,#01a783,#74eaff,#14ffa5);
}
span{
    position: absolute;
    background: #ffffff;
    /* 旋转 */
    transform: translate(-50%,-50%);
    /* 无法选中该元素,但是可以选中该元素下的元素 */
    pointer-events: none;

    border-radius: 50%;
    animation: animate 1s linear infinite;

}
@keyframes animate
{
    0%{
        width: 0px;
        height: 0px;
        /* 透明度 */
        opacity: 0.6;
    }
    100%{
        width: 700px;
        height: 700px;
        opacity: 0;
    }

}